Shoulder mortar



Aprll 1, 1952 c. E. SIMPSON SHOULDER MORTAR Filed Jan. 10, 1947 .9% G ff, www QW l NM, @I

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kthe recoil stroke.

Patented Apr. l, 1952 UNITE sri" QFFECE (Granted under the act of March 3, 1883, as amended April 3i), 1928; 370 0. G. 757) .6 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes Without the payment of any royalty thereon.

This invention relates to a shoulder mortar, more particularly to means for absorbing the recoil forces of the mortar.

Many weapons adapted to be fired from the shoulder, particularly weapons iiring a morta-r projectile have exceedingly high recoil forces which are dissipated largely against the shoulder of the rer. Numerous devices have been resorted to with the View of reducing the recoil force to reasonab-le limits but have not been particularly effective. Nearly all of such devices so utilized employ only spring means but obviously such means is to a large extent entirely inadequate because of the tremendous recoil forces inherent in shoulder mortars.

Accordingly it is an object of this invention to provide an improved shoulder mortar wherein the recoil thereof is substantially reduced.

The specic nature of the invention as weii as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a fragmentary view of a shoulder mortar embodying this invention shown in longi tudinal section with the hammer in the cocked or recoil position.

Fig. 2 is a view similar to Fig. 1 but showing the position of the barrel and hammer at the moment of discharge.

Briefly this invention consists of a shoulder mortar housing or receiver which contains a barrel mounted for limited longitudinal movement therein. A driving spring is contained within a tubular housing mounted in the rear of the receiver and is adapted to bear against the rear end portion of the firearm barrel to drive such forwardly after the compression of The firing pin is axially mounted in the breech end of the barrel and a hammer associated with the sliding barrel is arranged to strike the firing pin when such barrel is released by a trigger, hence discharge of the cartridge or shell is effected as the barrel is moving forwardly. c

In Fig. 1 there is shown in assembled relation a firearm embodying this invention. Such nrearm comprises mainly a cylindrical housing l5, a `barrel 20 and a buffer mechanism 25. Cylindrical housing l5 is provided with threads i5 on the rear end thereof and an end cap l1 is screwed 2 therein. End cap il has an axial hole I8 and a threaded axial recess le is provided on the rear face thereof. A buffer tube 2i having a closed rear end is threaded into recess i9.

Barrel 22 is provided with a breech cap 22 which may be secured to the rear end of barrel 2o by threads or other means (not shown). Breech cap 22 slidably engages the interior w-all surface of housing l5. A gland 23, preferably secured to the forward end of housing l5 by threads 2li, slidably supports the forward end of barrel 29 Within housing i5. A cylindrical eX- tension member 26 is secured to the rear end face of breech cap 22 preferably by brazing and the open rear end thereof. is closed by a circular end plate 2l. Such plate may be secured to cylindrical extension member 25 forming a charnber 23 immediately in back of breech cap 22.

A rearwardly projecting axially disposed boss 22 is provided on plate 2i and a tube 3D is horizontally secured to such boss by threads 3l, such tube being axially disposed within buffer tube 2l. A spring guide 32 is provided Within tube 3i] and is suitably secured at the rear Vend in a manner not shown. A spring 33 surrounds spring guide 32 and one end thereof abuts the .closed rear end of buffer tube A2l while the other end of spring 33 abuts an integral ange 34 provided on the inside of tube 30 as shown in Figs. 1 and 2. Spring 33 acts as a driving spring to force barrel 20 forwardly as well as to absorb the remaining recoil energy of Vthe barrel in a manner to .be later described.

An axial hoie35 is provided in breech cap 22 of suitable configuration to accommodate a firing pin 3B. Firing pin 36 has `a head portion .3l in the rear end thereof and a helical spring .38 surrounds firing pin 36, one end of such spring abutting head portion A3i while the other end abuts a suitable shoulder provided in firing pin hole l35. Spring 38 retracts firing pin 36 in a Well-known manner. A cap 39 is screwed onto a threaded boss 4d provided on the rear `face of breech cap -22 to retain firing pin 3S within hole 375.

A hammer 4l is pivotally mounted on a bracket 42 by a transverse pin 43. Bracket 42 is secured within chamber 28 as shown in Figs. 1 and 2, preferably by welding. 'A tang 443 integrally formed with hammer il is provided therein for a purpose to be later described. Such tang is vertically disposed when hammer @I lies in the horizontal position shown in IFig. gl. A longi-V tudinallydisposed slot i5 vis provided in the ,bottom of chamber 23 as shown in Figpl to permit the underside of housing I as shown in Figs.,

1 and 2. Lever 45 is pivotally mounted by a transverse pin 48 in a bracket 49 which in turn is secured to the underside of housing i5 preferably by brazing or welding. A vertically disposed slot 50 is provided in lever 45 and sear 41 is vertically mounted therein by a transverse pin 5I, such mounting permitting limited pivotal movement of sear 41. A slot 52 in the bottom of housing I5 permits sear 41 to project therethrough to eng-age a shoulder 53 provided on breech cap 22 to hold the barrel in the cocked position shown in Fig. 1.

A hammer tripping pawl 54 of lesser width than sear 41 is pivotally mounted on the underside of housing I5 somewhat ahead of such sear by a transverse pin 56 supported by a bracket 55. Pawl 54 is provided with a vertically disposed surface 51 which is arranged to engage tang i4 in a manner to be later described. A suitable spring 58 is placed about pin 56 to bias pawl 54 upwardly through a suitable slot 59 provided on the underside of housing I5 whereby surface 51 of such pawl lies in the path of hammer 4i. A suitably curved `arcuate surface 55 is pro vided on top of pawl 54 whereby such pawl may be cammed downwardly out of the path of hammer. 4I on the recoil stroke of barrel 26. A slot 63 is provided in breech cap 22 enabling such cap to slide over pawl 54 on either the recoil or counter-recoil stroke without interference from such pawl. Since pawl 54 is of lesser width than sear 41, slot 63, which is slightly wider than pawl 54, will permit passage therethrough of pawl 54 but does not permit passage therethrough of sear 41, which is wider than slot 63, whereby sear 41 normally engages shoulder 53. t

The mortar is readily cocked by forcing barrel rearwardly against the bias of spring 33 whereupon such spring is compressed. The sloped surface 6I provided on the front upper corner of sear 41 permits such sear to be cammed downwardly as breech cap 22 passes over sear 41 whereupon torsion spring 62 raises lever 45 and Sear 41 upwardly so that sear 41 engages shoul-V der 53 on breech cap 22 thereby securing barrel 20 in the cocked position shown in Fig. 1. A mortar projectile is then slid into position in barrel 2U, the mortar now being cocked and ready to re. Sear 41 is released by a downward push of lever 46 and barrel 20 with breech cap 22 and cylindrical extension member 26 moves forwardly due to the bias of spring 33.

Breech cap 22 passes over pawl 54, the slot 63 therein permitting such cap to nclear pawl 54. When tang 44 of hammer 4I strikes surface 51 of pawl 54, such hammer is rotated in a clockwise direction as shown in Fig. 2, striking ring pin 36 thereby effecting discharge of the cartridge contained within barrel 20. If for some reason the cartridge fails to explode, barrel 20 will continue forwardly until the forward edge of breech cap 22 strikes the rear surface of gland 23 thus stopping barrel 2U.

It will be apparent to those skilled in the art that before tang 44 strikes pawl 54, barrel 20 has attained considerable momentum. Therefore at the moment of discharge of the cartridge contained Within barrel 20, such barrel has a substantial forward inertia to be overcome before recoil of such barrel can be effected. It is this inertia produced by setting the barrel in motion before ring the cartridge which absorbs a substantial amount of the recoil energy developed by the explosion of the cartridge, thereby greatly lessening the remaining recoil forces to be absorbed by the buffer mechanism of the firearm.

It is desired to point out that the expanding brake shoes 64 as disclosed in my Patent No. 2,520,971 issued September 5, 1950 are utilized in conjunction with the device disclosed herein. Brake shoes 64 segmentally formed are slidably mounted in chordal slots 65 of cap 22 and are radially disposed to each other. Each shoe being provided with an outer arcuate surface complementary to the inner surface of housing I5 for cooperation therewith. The gas pressure developed in the housing by the explosion of the cartridge is transmitted to shoes 64 thereby forcp ing such shoes outwardly against the inner sur face of housing I5. By means of such shoes, considerably greater recoil forces can be absorbed which means that a projectile having a much greater propellent force can be utilized as desired.

From the foregoing description it is apparent that the shoulder mortar disclosed herein is constructed to substantially reduce the recoil forces so that the residual recoil force can be readily absorbed by the conventional buffer mechanism of the rearm and the shoulder of the shooter without harmful eifect to the shooter. It ,is further pointed out that the construction herein shown is simple and easy of operation and accordingly is inexpensive to manufacture. Such features are particularly desirable especially in times of war when mass production in large quantities are necessary.

I claim:

l. A rearm for discharging cartridges oomprising a housing, a buifer member mounted on the rear of said housing, a barrel with a Abreech cap secured thereto slidably mounted within the housing, means for releasably holding said barrel in a retracted position, a ring pin mounted in said breech cap of said barrel, a hammer vpivotally secured to said barrel, resilient means contained in said buffer member for urging said barrel forwardly upon release of said barrel holding means, and means engageable .by said hammer as said barrel moves forwardly to rotate said hammer into engagement with said ring pin thereby eecting discharge of a cartridge while said barrel is in motion whereby a substantial amount of the recoil energy imparted to said barrel is absorbed in overcoming the inertia of said barrel.

2. En combination, a shoulder mortar having a tubular housing, a .barrel slidably mounted in said housing for reciprocating movement, resilient means for urging said barre1 forwardly, said barrel being provided with a rearwardly disposed hollow extension and having frictional means therein which is actuated outwardly against said tubular housing upon discharge of a shell, means for holding said extension in the cocked position, and means for discharging the shell after said barrel has been released from the cocked .position and while said barrel is moving forwardly 'whereby said frictional means and the added inertia of said forwardly moving barrel absorb -a-V substantial portion of the recoil energy imparted to said barrel.

3. In combination, a shoulder mortar having a tubular housing, a barrel slidably mounted in said housing for reciprocating movement, resilient means for urging said barrel forwardly, said barrel being provided with a rearwardly disposed hollow extension and having frictional means radially disposed therein which is actuated outwardly against said tubular housing upon discharge of a shell, said extension being provided with a downwardly depending sear engaging shoulder, sear means mounted on said housing for engagement with said shoulder of said extension when said barrel is in the cocked position, and means for discharging the shell after said barrel has been released from the cocked position and while said barrel is moving forwardly whereby said frictional means and the added inertia of said forwardly moving barrel absorb a substantial portion of the recoil energy imparted to said barrel.

4. In combination, a shoulder mortar having a tubular housing, a barrel slidably mounted in said housing for reciprocating movement, resilient means for urging said barrel forwardly, a breech cap iixedly secured to 'said barrel, a plurality of brake shoes radially disposed and slidably mounted in said breech cap which are actuated outwardly against said tubular housing upon discharge of a shell, said breech cap being provided with a downwardly depending sear engaging shoulder and a rearwardly disposed hollow extension, said extension having a longitudinal slot therein, a hammer pivotally mounted within said extension, a lug on said hammer projecting downwardly through said slot, sear means mounted on the housing for engagement with said shoulder of said breech cap when said barrel is in the cocked position, and means pivotally mounted o-n said housing for engagement with said lug after release of said barrel whereby said hammer is rotated to effect discharge of a shell in said barrel after said barrel has moved a substantial distance forwardly and while said barrel is in motion and thereby cause the pressure of the gases to be partly expended upon said barrel and said brake shoes for resisting and arresting the forward movement of said barrel and the remaining pressure of the gases to return said .barrel to the cocked position.

5. In a firearm having a housing, a barrel mounted for limited longitudinal movement therein, resilient means for urging said barrel forwardly, a breech cap xedly secured to said barrel, said breech cap being provided with a downwardly depending rear engaging shoulder o and a rearwardly disposed hollow extension, said extension having a longitudinal slot therein, a

hammer pivotally mounted within said extension, a lug on said hammer projecting downwardly through said slot, sear means mounted on the housing for engagement with said shoulder of said breech cap when said barrel is in the recoil position, and means pvotally mounted on the housing for engagement with said lug after the release of said barrel whereby said hammer is rotated to effect discharge of a cartridge in said barrel after said Abarrel has moved a substantial distance forwardly and while said Ibarrel is in motion.

6. In a firearm having a housing, a barrel slidably mounted for longitudinal movement within said housing, resilient means for urging said barrel forwardly, means limiting the longitudinal movement thereof, said barrel having a rearwardly disposed hollow extension, said extension being provided with a longitudinal slot and a downwardly depending shoulder forwardly thereof, a hammer mounted in said extension, a lug on said hammer extending downwardly through said slot, sear means mounted on the housing for engagement with said shoulder of said extension in a recoil position, said resilient means being provided to drive said barrel forwardly upon the release of said sear means, and means projecting through the housing for engagement with said lug as said barrel passes over said last-mentioned means to rotate said hammer thereby discharging a cartridge in said barrel while said barrel is moved forwardly whereby a substantial reduction of the recoil force is obtained.

CLARENCE E. SIMPSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 891,778 Mertens June 23, 1908 994,156 Haussner June 6, 1911 1,144,285 Becker June 22, 1915 2,218,877 Ernesti et al Oct. 22, 1940 2,399,432 Gazda Apr. 3Q, 1946 2,520,971 Simpson Sept. 5, 1950 FOREIGN PATENTS Number Country Date 20,017 Austria May 10, 1905 228,414 Germany Dec. 2, 1908 

